Self-Assembly Of Poly(?-caprolactone)-s-s-Polystyrene In Nanoparticles

Block copolymers, which consist of polymer blocks with thermodynamicincompatibility, exhibit a variety of self-assembled ordered microphases. Recentreports have demonstrated that block copolymers confined in emulsion nanoparticlesself-assemble into ordered phase-separated morphologies. And these block copolymerself-assemblies have great potential as catalytic supports, catalysis, drug delivery.Currently, most previous researches have focused mainly on the the addition ofhomopolymer and the commensurability between the characteristic length D of thenanoparticles and the block copolymer domain spacing L0. However, the influence ofdifferent kinds of surfactants on the self-assembled morphologies of polymernanoparticles has been reported rarely.Here, two aspects are mainly explored in this paper.1. The self-assembled structures of PCL-s-s-PS block polymer nanoparticleswith different kinds of ionic surfactants. PCL-s-s-PS was synthesized by combinationof ATRP and ROP using a heterobifunctional initiator with a disulfide bond, thestructure of PCL-s-s-PS were characterized by GPC and1H-NMR. Then, blockpolymer nanoparticles were prepared by emulsion method using sodiumdodecylbezene sulfonate (SDBS) or hexadecyl trimethy ammonium bromide (HTAB)as surfactants. The stability of two emulsion samples was observed and self-assemblymorphologies were studied by DLS and TEM.2. The self-assembled structures of PCL-S-S-PS/N+-PS blend nanoparticleswith N+-PS as macromolecule surfactant. Quaternized polystyrene homopolymerN+-PS was synthesized by ATRP using quaternized initiator. N+-PS can not only beused as macromolecule surfactant, but also vary the composition of polymernanoparticles, PCL-s-s-PS/N+-PS blend nanoparticles were prepared andmorphologies were studied by TEM and DLS before and after cleavage reaction of thedisulfide bonds in nanoparticles by Bu3P.